Implement relative pointer mode on Wayland

yasl_surface_set_pointer_mode(YASL_POINTER_RELATIVE) now takes a
persistent zwp_locked_pointer_v1 on the surface and hides its cursor.
While the compositor keeps the lock engaged, zwp_relative_pointer_v1
motion is pushed as POINTER_MOTION with pos frozen and delta in device
pixels. When the lock disengages, as on focus loss, motion is absolute
again with a delta derived by the input queue.

The lock follows the pointer's seat: it moves to another seat when its
seat loses the pointer, and is released on NORMAL and on surface
destruction. Compositors without both protocols return false.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/src/platform/wayland/internal.h b/src/platform/wayland/internal.h
index d619dba..c35db7f 100644
--- a/src/platform/wayland/internal.h
+++ b/src/platform/wayland/internal.h
@@ -23,6 +23,8 @@
 #include "protocols/commit-timing-v1-client-protocol.h"
 #include "protocols/xdg-toplevel-drag-v1-client-protocol.h"
 #include "protocols/primary-selection-unstable-v1-client-protocol.h"
+#include "protocols/relative-pointer-unstable-v1-client-protocol.h"
+#include "protocols/pointer-constraints-unstable-v1-client-protocol.h"
 
 #include <fcntl.h>
 #include <limits.h>
@@ -131,6 +133,7 @@ struct seat {
     struct wl_pointer *pointer;
     struct wl_touch *touch;
     struct wp_cursor_shape_device_v1 *cursor_shape_dev;
+    struct zwp_relative_pointer_v1 *relative_pointer;
     struct wl_surface *cursor_surface;
     struct wp_viewport *cursor_viewport;
     struct zwp_tablet_seat_v2 *tablet_seat;
@@ -212,6 +215,8 @@ struct wayland_display {
     struct wl_data_device_manager *data_manager;
     struct zwp_primary_selection_device_manager_v1 *primary_selection_mgr;
     struct wp_cursor_shape_manager_v1 *cursor_shape_mgr;
+    struct zwp_relative_pointer_manager_v1 *relative_pointer_mgr;
+    struct zwp_pointer_constraints_v1 *pointer_constraints;
     struct wl_cursor_theme *cursor_theme;
     const char *cursor_theme_name;
     struct zwp_tablet_manager_v2 *tablet_mgr;
@@ -275,6 +280,9 @@ struct wayland_surface {
     struct wp_fifo_v1 *fifo;
     struct wp_commit_timer_v1 *commit_timer;
     struct wl_callback *frame_cb;
+    /* Persistent lock held while relative; lock_seat owns the locked wl_pointer. */
+    struct zwp_locked_pointer_v1 *pointer_lock;
+    struct seat *lock_seat;
     const struct yasl_window_cbs *cbs;
     void *ud;
     uint64_t frames_skipped;
@@ -316,6 +324,8 @@ struct wayland_surface {
     bool destroyed;
     bool opaque;
     bool want_draw;
+    bool relative;
+    bool pointer_locked;
 };
 
 
@@ -388,6 +398,7 @@ int  seat_modifiers(const struct seat *s);
 void surface_init_cursor(struct wayland_display *c);
 void seat_destroy_tablet(struct seat *s);
 void seat_pointer_reset(struct seat *s);
+void surface_unlock_pointer(struct wayland_surface *w);
 
 extern const struct zwp_text_input_v3_listener text_input_listener;
 void ime_reset(struct wayland_surface *w);